Fix/clean errors (#191)

* clean dev errors

* add check command

* yarn -> npm in travis

* fix all warnings

* fix base test

* 💄

.travis.yml

@@ -5,11 +5,10 @@ cache:
   directories:
     - node_modules
 before_script:
-  - npm install -g yarn
   - cp example.config.js config.js
 install:
-  - yarn
+  - npm install
 script:
-  - yarn lint
-  - yarn build
-  - yarn test
+  - npm run lint
+  - npm run build
+  - npm run test